Determination of chloro- and methylthiotriazine compounds in human urine: extraction with diethyl ether and C-18 solid-phase extraction for gas chromatographic analysis with nitrogen-selective and electron capture detection

This paper describes an evaluation of extraction methods of triazine herbic ides atrazine, simazine, prometryn, and ametryn and of three chlorodealkyla ted atrazine metabolites from human urine using diethyl ether and C-18 soli d-phase extraction (Sep-Pak C-18 cartridges). The extracts were analysed by capillary gas chromatography using nitrogen selective and electron capture detectors. At ng ml(-1) concentrations the diethyl ether extraction recove ries of atrazine and simazine were almost quantitative (R.S.D. 10%), while the recoveries of other triazines ranged from 58% for deisopropylatrazine t o 85% for deethylatrazine (R.S.D. 19-34%). The sensitivity of the method us ing a nitrogen selective detector ranged from 5 ng ml(-1) for atrazine to 3 0 ng ml(-1) for didealkylated atrazine. C-18 solid-phase extraction with ac etone as eluting solvent resulted in about 100% recoveries of all parent he rbicides (R.S.D. 15-21%) with detection limits of 5 ng ml(-1) for atrazine and 10 ng ml(-1) for other herbicides. Comparably high recoveries of three dealkylated atrazine metabolites (R.S.D. 10-12%) were achieved from acidifi ed urine samples (pH 2-3) only at concentrations lower than 100 ng ml(-1). The diethyl ether extraction procedure served to identify occupational expo sure to atrazine and simazine. Deethyldeisopropylatrazine was confirmed as the predominant urinary dealkylated metabolite followed by monodealkylated metabolites and unchanged atrazine. (C) 2000 Elsevier Science B.V. All righ ts reserved.